1. Field of the Invention
The present invention relates to a single lens reflex camera having a replaceable view finder, and, more particularly, it relates to a single lens reflex camera having a replaceable view finder wherein a view finer unit includes an electric circui therein, which electric circuit can be connected to an electric circuit arranged in a body of the camera through contact means.
2. Related Background Art
Various single lens reflex cameras wherein a view finder can be replaced by another one according to its purpose of usage have been put to practical uses, and such cameras having a replaceable view finder including an electric circuit therein have also been proposed. In these conventional single lens reflex cameras, for example, in the case where a light receiving element for the TTL light measurement is arranged in a finder, as disclosed in the U.S. Pat. No. 3,967,299, as well as in the case where an accessory shoe with a synchronizing contact is provided in a replaceable view finder, as disclosed in the Japanese Patent laid-Open No. 57-135934, it is required to provide an electric contact for the signal transmission between the camera body and the finder so that the electric circuit in the replaceable finder can be electrically connected to the electric circuit in the camera body when the finder is mounted on the camera body.
In the above Japanese Patent Laid-Open No. 57-135934 and the above U.S. Pat. No. 3,967,299, as shown in FIG. 3, electric contact members 3a and 3b were arranged in a space between a third reflection surface la of a pentagonal roof prism (pentaprism) 1 and a camera body 2. This arrangement is effective to obtain the electric connection between the camera body and the view finder unit, both when the view finder unit is mounted on the camera body 2 by dropping or lowering the finder unit on a mount portion of the camera body and when the finder unit is mounted on the camera body by sliding the finder unit forwardly on the camera body.
However, the position (in the camera body) where such contact member is arranged must be applied to various important uses, as for example, the use for arrangement of an indicator for providing an indication compartment in a view field in the finder. More particularly, there is no problem when only the contact member is arranged in such position; however, when a plurality of contact members are required as described in the above U.S. Pat. No. 3,967,299, if all of the contact members are arranged in such position, there arises a problem that a position where the indicator is to be arranged is considerably limited or restricted.
Further, there has been provided a single lens reflex camera wherein, as shown in FIG. 4, a pair of contact mechanisms 4a and 4b were arranged on the camera body 2 outwardly (rightwardly and leftwardly) beyond the both sides of the pentagonal roof prism 1 to permit the electric connection between an exposure meter in the view finder unit and a power battery in the camera body. This system is particularly applicable in the case where the view finder unit is mounted on the camera body by dropping the former on the latter, and is advantageous in the point that the number of contacts to be arranged can be increased since both sides of the pentaprism 1 are available and since plurality of contacts can be arranged on each side of the pentaprism in parallel to the side surface of the pentaprism (i.e., in parallel to an optical axis of the lens).
However, in this case, there arises a problem that a transverse width of the view finder unit must naturally be lengthened to permit the arrangement of the contact members thereon in correspondence to the associated contact members arranged on the camera body 2 and situated outwardly of the pentaprism.